At present an "Adidas" ski binding is widely used, that consists of a plate with side-frames set at an angle to the longitudinal axis of the ski. The plate size and the value of the side-frames slope are determined by the size and shape of the boot sole toe. The binding is designed for use with a ski boot that has a projecting toe portion of the boot sole. The binding lock is designed in the following way. The plate carries a pin to which a lever is fixed that has still another pin at its free end. To this latter pin a second lever is fixed in its turn, the free end thereof holding down the flange of the boot sole toe portion. To lock the boot, the skier must rest the end of the second lever against the boot flange and press the first lever which in this case keeps turning until the line connecting the two pins becomes lower than the line connecting the first pin with the rest point. In this position the boot gets locked. Disadvantages of said binding include its considerable weight, low adaptability to manufacture, relative complexity of the lock design and considerable torques arising in the plane perpendicular to the boot sole surface when the skier pushes, the latter disadvantage being especially serious when a skating stride is used. Strong sole twisting is caused not only by the binding design but also by a narrow sole toe portion of a standard "Racing Norm 38" type boot which has a narrower toe as compared to a "Racing Norm 50" boot.
A ski binding of the "Rotafella" type is widely used nowadays. This binding is also designed as a plate with side-frames set at an angle to the longitudinal axis of the ski. As distinct from the "Adidas" binding it has three pins directly on the plate, which mate with the corresponding holes in the boot sole toe portion. The boot is locked with a shackle, free ends of which are set in sleeves of the side-frames. In the foremost part of the binding there is an axle carrying a notched plate. The boot is placed in such a way that the holes in the boot sole toe portion mate with the pins. Then the skier presses the shackle into engagement with one of the notches in the plate. The binding may have different types of locks depending on the modification. Secure boot locking and a smaller torque occuring in the plane perpendicular to the ski longitudinal axis as compared to the "Adidas" binding mentioned above may be cited as advantages of said binding. Disadvantages include its considerable weight, relatively low adaptability to manufacture and relative complexity of the lock manufacture.
There is a prior art ski binding comprising rest pins, of two parts each (cf. laid-open FRG Patent Application No. 3240750). One part of the pin is directly fixed in the ski (boot) body, and the other part fits in a corresponding hole in the boot (ski). If the bottom part of the pin is fixed in the ski body, then, in order to lock the boot it is necessary to place it so that upper parts of the pins fit in the corresponding holes in the boot sole toe portion. To restrain the boot vertical movement various locks are employed. Advantages of said binding include relatively high adaptability to manufacture and simple design, its quick mounting and dismantling, use of different types of locks. Disadvantages include relatively poor functional qualities of the binding when locking and unlocking the boot because this can be done only manually.
A prior art binding (cf. FRG Patent No. C 8425984.I) comprises ski-mounted rest pins for mating with corresponding holes in the boot sole toe portion and a lock featured as a bracket-shaped blade spring one end thereof attached to the ski while the other is designed to straddle from above the boot sole toe portion. High adaptability to manufacture, low production cost, small overall dimensions, light weight, automatic (no need to use hands) locking of the boot to the ski may be cited among its advantages. But this binding may be used only with ski boots that have a projecting sole toe portion or a welt. Accordingly, if a horizontal component force perpendicular to the ski longitudinal axis occurs when the skier pushes, then a substantial torque is developed, so the skier's push zone does not coincide with the boot lock zone. Said disadvantage is characteristic of all types of binding designed for use with the projecting boot toe portion and is most clearly manifested when a skating stride is used.